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UKMT Junior Kangaroo, 2015

Combinatorics Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

The diagram below shows a sequence of shapes made up of black and white floor tiles where each shape after the first has two more rows and two more columns than the one before it. How many black tiles would be required to create the 15th shape in the sequence?

(A) $401$ (B) $421$ (C) $441$ (D) $461$ (E) $481$

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